Question: Complete the recursive formula of the arithmetic sequence $-1, -13, -25, -37,...$. $a(1)=$
The first term is $-1$ and the common difference is $-12$. ${-12\,\curvearrowright}$ ${-12\,\curvearrowright}$ ${-12\,\curvearrowright}$ $-1,$ $-13,$ $-25,$ $-37,...$ This is the recursive formula of $-1, -13, -25, -37,...$ $\begin{cases} a(1)=-1 \\\\ a(n)=a(n-1)+(-12) \end{cases}$